Coronary Artery Rings Research Articles

Vasoactive properties of hydro-methanol pod powder extract of Acacia nilotica in porcine coronary artery: Role of Nitric Oxide (NO)

Background: Acacia nilotica is a plant used in traditional medicine in Senegal for treatment of high blood pressure. The aim of this study was to determine whether a hydro-methanolic pod powder extract of Acacia nilotica (MSAN01) can induce a relaxant effect in porcine coronary arteries and to elucidate the underlying mechanism. Methods: Porcine coronary artery rings were suspended in organ chambers to record changes in isometric forces. Rings with intact endothelium were incubated with or without L-Nitro Arginine (L-NA, 300 µM) to block NO synthase; 1,12 bis[(2-methylquinolin-4-yl)amino]dodecane (UCL, 100 nM), an inhibitor of small-conductance calcium-activated potassium channels (SKCa); and Tram-34 (1 µM), an inhibitor of intermediate-conductance calcium-activated potassium channels (IKCa); or indomethacin (INDO, 10 µM), a cyclooxygenase inhibitor, before contraction with U46619 (1-60 nM), a thromboxane A2 analogue, and subsequent generation of a concentration-relaxation curve to hydro-methanolic pod powder extract of Acacia nilotica (MSAN01). In some experiments, the endothelium was removed before contraction with U46619 (1-60 nM) and concentration-relaxation with MSAN01. Bradykinin was used to verify the presence of functional endothelium. Results: Exposure The hydro-ethanolic pod powder extract of Acacia nilotica induces a vasodilatory effect in porcine coronary arteries pre-contracted with U46619. This effect is endothelium-dependent and mediated by nitric oxide (NO). Conclusion: It Acacia nilotica induces vascular relaxation, which may explain the beneficial effects of this plant in the treatment of high blood pressure in Africa.

ATP citrate lyase drives vascular remodeling in systemic and pulmonary vascular diseases through metabolic and epigenetic changes.

ATP citrate lyase (ACLY), a crucial enzyme in de novo lipid synthesis and histone acetylation, plays a key role in regulating vascular smooth muscle cell (VSMC) proliferation and survival. We found that human coronary and pulmonary artery tissues had up-regulated ACLY expression during vascular remodeling in coronary artery disease and pulmonary arterial hypertension. Pharmacological and genetic inhibition of ACLY in human primary cultured VSMCs isolated from the coronary arteries of patients with coronary artery diseases and from the distal pulmonary arteries of patients with pulmonary arterial hypertension resulted in reduced cellular proliferation and migration and increased susceptibility to apoptosis. These cellular changes were linked to diminished glycolysis, reduced lipid synthesis, impairment in general control nonrepressed protein 5 (GCN5)-dependent histone acetylation and suppression of the transcription factor FOXM1. In vivo studies using a pharmacological inhibitor and VSMC-specific Acly knockout mice showed that ACLY inhibition alleviated vascular remodeling. ACLY inhibition alleviated remodeling in carotid injury and ligation models in rodents and attenuated pulmonary arterial hypertension in Sugen/hypoxia rat and mouse models. Moreover, ACLY inhibition showed improvements in vascular remodeling in human ex vivo models, which included cultured human coronary artery and saphenous vein rings as well as precision-cut lung slices. Our results propose ACLY as a novel therapeutic target for treating complex vascular diseases, offering promising avenues for future clinical intervention.

Functional Adaptations in Coronary Reactivity following Healthy Pregnancy in Swine

Introduction: This study was designed to test the hypothesis that coronary artery adaptations during the postpartum period are related to underlying reductions in endothelium-dependent relaxation and/or augmented smooth muscle vasoconstrictor responsiveness. Methods: In vivo experiments were performed in control (nonpregnant) and postpartum swine 35–45 days of postdelivery, with isometric tension experiments performed in isolated coronary arteries from those animals. Results: Coronary artery rings demonstrated increases in active tension generation following incremental increases in passive stretch with no differences between groups. Endothelium-dependent relaxation to bradykinin was attenuated in arteries from postpartum swine versus control (p < 0.005). Concentration-dependent contractions to the thromboxane A2 mimetic U46619 (0.1 nm–1 µm) were shifted rightward (EC50 27 ± 10 nm vs. 238 ± 66 nm; p < 0.01) in arteries from postpartum swine, with no changes in maximum contractile responses (p = 0.68). Intracoronary administration of U46619 (1 nm–1 µm) in open-chest swine decreased coronary blood flow ∼45 ± 3% in nonpregnant controls but had no effect on coronary blood flow in postpartum swine. Concentration-dependent contractions to KCl (5–90 mm) showed a rightward shift in arteries from postpartum swine (15.6 ± 1.4 mm vs. 21.8 ± 1.9 mm; p = 0.03), with no change in maximum response. Taken together, the postpartum period is associated with reduced endothelium-dependent relaxation and responsiveness to receptor-dependent and -independent vasoconstrictor stimuli. Conclusion: These findings indicate that chronic exposure of the coronary circulation to the pregnancy/postpartum milieu results in functional adaptations in sensitivity to paracrine/hormonal compounds that should be further explored.

Danggui Buxue Decoction and its components dilate coronary artery through activating the inward rectification K+ channels pathway

Ethnopharmacological relevanceDanggui Buxue Decoction (DBD), a classic representative prescription of invigorating Qi and producing blood, is used to treat coronary heart disease angina pectoris and vascular injury diseases. Abnormal coronary artery is an important cause of cardiovascular disease. However, the mechanism of DBD dilates coronary arteries is still unclear. Aim of the studyThis study aimed to elucidate the impacts and distinctions among DBD, Astragalus, Angelica sinensis, and identified active components on pre-constricted coronary arteries, as well as to delve deeper into their respective mechanisms. Materials and methodsAfter the preconstriction of a rat isolated coronary artery ring with either 30 mM KCl or 200 nM U46619, the vascular tension was observed following the addition of DBD, and other components. Subsequently, the impact of these active components on coronary blood flow (CBF) was confirmed through in vivo testing. Further investigation into the underlying mechanism was carried out using a combination of blockers, molecular docking, surface plasmon resonance (SPR), cell heat transfer analysis (CETSA), and patch-clamp techniques. ResultsIn vitro experiments showed that DBD and its components butylidenephthalide, ligustilide, calycosin, and quercetin could dilate coronary artery preconstricted with either 30 mM KCl or 200 nM U46619. In addition, the active ingredient was found to significantly increase CBF. Mechanistically, BaCl2 was found to reduce the relaxation effect of the drug by adding a blocker. Molecular docking, SPR and CETSA results showed that the active ingredients had a strong binding potential with inward rectification K+ channels (KIR) channel protein. Patch clamp studies demonstrate that quercetin can increase KIR current, and BaCl2 can significantly reduce its current. ConclusionsThe active components of DBD, butylidenephthalide, ligustilide, calycosin, and quercetin, activate KIR channels to relax coronary artery and increase CBF.

Amphetamine increases vascular permeability by modulating endothelial actin cytoskeleton and NO synthase via PAR-1 and VEGF-R

Abuse of amphetamine-type stimulants is linked to cardiovascular adverse effects like arrhythmias, accelerated atherosclerosis, acute coronary syndromes and sudden cardiac death. Excessive catecholamine release following amphetamine use causes vasoconstriction and vasospasms, over time leading to hypertension, endothelial dysfunction or even cardiotoxicity. However, immediate vascular pathomechanisms related to amphetamine exposure, especially endothelial function, remain incompletely understood and were analyzed in this study. Pharmaco-pathological effects of acute d-amphetamine-sulfate (DAM) were investigated ex vivo using contraction–force measurements of rat carotid artery rings and in vitro using label-free, real-time electrochemical impedance spectroscopy (EIS) on endothelial and smooth muscle cells. Specific receptor and target blocking was used to identify molecular targets and to characterize intracellular signaling. DAM induced vasodilation represented by 29.3±2.5% decrease in vascular tone (p<0.001) involving vascular endothelial growth factor receptor (VEGF-R) and protease activated receptor 1 (PAR-1). EIS revealed that DAM induces endothelial barrier disruption (−75.9±1.1% of initial cellular impedance, p<0.001) also involving VEGF-R and PAR-1. Further, in response to DAM, Rho-associated protein kinase (ROCK) mediated reversible contraction of actin cytoskeleton resulting in endothelial barrier disruption. Dephosphorylation of Serine1177 (−50.8±3.7%, p<0.001) and Threonine495 (−44.8±6.5%, p=0.0103) of the endothelial NO synthase (eNOS) were also observed. Blocking of VEGF-R and PAR-1 restored baseline eNOS Threonine495 phosphorylation. DAM induced vasodilation, enhanced vascular permeability and actin cytoskeleton contraction and induced eNOS hypophosphorylation involving VEGF-R, PAR-1 and ROCK. These results may contribute to a better understanding of severe adverse cardiovascular effects in amphetamine abuse.

Effects of the thromboxane receptor antagonist S18886 in the porcine coronary circulation

Thromboxane A2 (TxA 2 ) is a potent coronary vasoconstrictor that has been implicated in promoting decreases in myocardial perfusion in a variety of (patho)-physiologic conditions. S18886 is a promising orally-active TxA 2 receptor antagonist currently approved for investigational clinical use. However, the coronary vascular effects of S18886 are unknown and its specificity and affinity for the thromboxane receptor in the coronary circulation remain unclear. We tested the hypothesis that administration of S18886 dose-dependently attenuates coronary vasoconstriction to the TxA 2 mimetic U46619 without influencing coronary responses to prostaglandin F 2α , acetylcholine, or smooth muscle depolarization (K + ). Experiments to test this hypothesis were performed in male (n = 5) and female (n = 6) domestic swine. Hearts were excised and the left circumflex coronary artery isolated, cleaned of periadventitial fat, and cut into 3 mm rings. Isometric tension of coronary artery rings was measured in response to log order increments of U46619 (1 nM to 1 μM) with and without S18886 (0.1-100 nM). Similar isometric studies were conducted with prostaglandin F 2α (10 nM-10 μM), acetylcholine (0.1-10 μM), and KCl (5-90 mM). U46619 induced concentration dependent increases in tension development of isolated coronary artery rings (average EC50 of 42 ± 19 nM). Incubation of coronary arteries with S18886 (1 nM) significantly attenuated coronary vasoconstriction to U46619 resulting in a rightward shift of the EC50 to 187 ± 38 nM (P &lt; 0.02). Vehicle had no effect on U46619-induced contractions. Higher concentrations of S18886 (10nM and 100nM) dose-dependently reduced U46619-induced contractions by 77% ± 3 and 93% ± 6 respectively. S18886 (1 nM) antagonized coronary vasoconstriction of prostaglandin F2α (10 μM) by 68% ± 5 (P &lt; 0.0001) but had no effect on either acetylcholine or KCl-induced contraction. Data from this investigation indicate that S18886 is an effective antagonist of U46619-induced vasoconstriction in the porcine coronary circulation. While S18886 does not influence coronary smooth muscle response to either acetylcholine or activation of L-type Ca 2+ channels, attenuation of prostaglandin F 2α suggests the antagonists specificity may extend beyond TxA 2 receptor signaling. NIH R01HL158723 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Calciprotein Particles Induce Endothelial Dysfunction by Impairing Endothelial Nitric Oxide Metabolism.

Calciprotein particles (CPPs) are associated with the development of vascular calcifications in chronic kidney disease. The role of endothelial cells (ECs) in this process is unknown. Here, we investigated the interaction of CPPs and ECs, thereby focusing on endothelial nitric oxide metabolism and oxidative stress. CPPs were generated in calcium- and phosphate-enriched medium. Human umbilical vein endothelial cells were exposed to different concentrations of CPPs (0-100 µg/mL) for 24 or 72 hours. Ex vivo porcine coronary artery rings were used to measure endothelial cell-dependent vascular smooth muscle cell relaxation after CPP exposure. Serum samples from an early chronic kidney disease cohort (n=245) were analyzed for calcification propensity (measure for CPP formation) and nitrate and nitrite levels (NOx). CPP exposure for 24 hours reduced eNOS (endothelial nitric oxide synthase) mRNA expression and decreased nitrite production, indicating reduced nitric oxide bioavailability. Also, 24-hour CPP exposure caused increased mitochondria-derived superoxide generation, together with nitrotyrosine protein residue formation. Long-term (72 hours) exposure of human umbilical vein endothelial cells to CPPs induced eNOS uncoupling and decreased eNOS protein expression, indicating further impairment of the nitric oxide pathway. The ex vivo porcine coronary artery model showed a significant reduction in endothelial-dependent vascular smooth muscle cell relaxation after CPP exposure. A negative association was observed between NOx levels and calcification propensity (r=-0.136; P=0.049) in sera of (early) chronic kidney disease patients. CPPs cause endothelial cell dysfunction by impairing nitric oxide metabolism and generating oxidative stress. Our findings provide new evidence for direct effects of CPPs on ECs and pathways involved.

Contribution of calcium dysregulation to impaired coronary artery contraction in Zucker diabetic fatty rats.

Diabetic coronary artery injury is closely associated with Ca2+ dysregulation, although the underlying mechanism remains unclear. This study explored the role and mechanism of Ca2+ handling in coronary artery dysfunction in type 2 diabetic rats. Zucker diabetic fatty (ZDF) rats were used as the type 2 diabetes mellitus model. The contractility of coronary artery rings induced by KCl, CaCl2 , 5-HT and U46619 was significantly lower in ZDF rats than in Zucker lean rats. Vasoconstriction induced by 5-HT and U46619 was greatly inhibited by nifedipine. However, in the presence of 1μM nifedipine or in the Ca2+ -free KH solution containing 1μM nifedipine, there was no difference in the vasoconstriction between Zucker lean and ZDF rats. Store-operated calcium channels (SOCs) were not involved in coronary vasoconstriction. The downregulation of contractile proteins and the upregulation of synthesized proteins were in coronary artery smooth muscle cells (CASMCs) from ZDF rats. Metformin reversed the reduction of vasoconstriction in ZDF rats. Taken together, L-type calcium channel is important for regulating the excitation-contraction coupling of VSMCs in coronary arteries, and dysregulation of this channel contributes to the decreased contractility of coronary arteries in T2DM.

Abstract 10442: Protective Effect of Inhibition of Sglt2 on Nanoplastics-Induced Premature Endothelial Senescence and Dysfunction

Background: Nanoplastics (NPs) are now widely acknowledged as a vital part of environmental pollution. However, the effects of NPs on the cardiovascular system are not well understood. We previously reported that NPs induce premature endothelial senescence and dysfunction via a redox-sensitive signaling pathway. Increasing evidence has shown that SGLT2 inhibitors (gliflozins) exhibit protective effects against the development of major cardiovascular diseases. Objective: This study aimed to investigate the role of SGLT2 on NPs-induced premature endothelial senescence and dysfunction, and, if so, to assess the effect of SGLT2 inhibition. Methods: Porcine coronary artery (PCA) rings and cultured endothelial cells (ECs) were exposed to NPs in the presence or absence of the SGLT2 inhibitor, Enavogliflozin (ENA), and the level of SGLTs expression, senescence-associated-beta galactosidase (SA-β-gal) activity, senescence markers, oxidative stress level, and vascular function were evaluated. Results: NPs were internalized in ECs in a time- and concentration-dependent manner. Exposure of PCAECs to NPs significantly up-regulated SGLT2 expression and increased SA-β-gal activity, one of the prominent senescence markers. ENA significantly reduced the NPs-induced increase of SA-β-gal activity in PCA and PCAECs. In addition, ENA prevented the NPs-induced up-regulation of senescence markers, p53, and p21 that promoted the inhibition of ECs proliferation. ENA prevented also the NPs-induced oxidative stress and up-regulation of NOX2 and p22phox in ECs. Exposure of coronary artery rings to NPs blunted endothelium-dependent relaxation and decreased the expression level of endothelial nitric oxide synthase level, and both of these effects were prevented by ENA. Conclusion: The present findings indicate that premature endothelial senescence and dysfunction induced by nanoplastics involve, at least in part, an upregulation of SGLT2, which is associated with increased levels of oxidative stress and the down-regulation of eNOS. They further raise the possibility that SGLT2 may be a potential target for preventing and/or treating environment pollution-associated cardiovascular diseases.

Deleterious effect in endothelin receptor–mediated coronary artery smooth muscle contractility in high-salt diet rats

Background and aimsHigh-salt diet has been suggested to increase the risk of heart disease. However, the mechanisms underlying coronary artery tension dysfunction caused by high-salt diet are unclear. Previous studies have shown that coronary artery spasm is often induced by endothelin-1 (ET-1) and thromboxane, leading to myocardial ischemia, while the store-operated Ca2+ entry (SOCE) function of coronary smooth muscle is very important in this process. Methods and resultsTension measurements of endothelium-denuded coronary artery ring segments showed that vasocontraction induced by U46619, ET-1, orSTIM1/Orai1-mediated SOCE was significantly lower in 4% high-salt diet rats than in control rats fed a regular diet. The results of western blotting and immunohistochemistry assays showed lower expression levels of endothelial receptors ETA and ETB, STIM1 and Orai1 in coronary artery of high-salt intake rats compared with control rats. Fibrosis was observed by using Masson's trichrome staining and picrosirius red staining. The plasma ET-1 concentration in high-salt diet rats was significantly higher than that of controls. The interventricular septum and posterior wall of high-salt diet rats were significantly thickened. ConclusionOur findings indicated that coronary artery tension was significantly decreased in 4% high-salt diet rats and that this decrease may be due to the change of endothelin receptor and its downstream pathway SOCE related protein expression in coronary artery. Coronary fibrosis was observed in rats fed with high-salt diet. This study provides potential mechanistic insights into high-salt intake–induced heart disease.

Carissa edulis Vahl (Apocynaceae) extract, a medicinal plant of Benin pharmacopoeia, induces potent endothelium-dependent relaxation of coronary artery rings involving nitric oxide

BackgroundHypertension is a major cardiovascular risk factor that affects most countries including those of Africa. Although Carissa edulis Vahl, Diodia scandens Sw. and Cleome gynandra L. are traditionally used in Benin as antihypertensive treatments with some efficacy mentioned by the local population, their biological activity on the cardiovascular system remains poorly studied. AimThe study investigated the vasoreactivity of the plants and assessed the underlying mechanisms using isolated arteries. Study designAqueous-ethanolic extracts of aerial parts of C. edulis, D. scandens and C. gynandra were prepared by maceration before being subjected to multi-step liquid-liquid fractionation with solvents of increasing polarity. The vasoreactivity of the extracts and fractions were assessed on isolated porcine coronary artery and rat aorta using organ chambers, the role of nitric oxide (NO) using NG-nitro-L-arginine (NO synthase inhibitor), prostanoids using indomethacin (cyclooxygenases inhibitor) and endothelium-dependent hyperpolarization using TRAM-34 plus UCL 1684 (inhibitors of calcium-dependent K+ channels), and the vascular uptake of polyphenols using Neu reagent. ResultsThe aqueous-ethanolic crude extract of C. edulis (CECE) induced potent relaxations that were exclusively endothelium-dependent and more pronounced than those to D. scandens and C. gynandra. The n-butanolic fraction of C. edulis (CEBF) was more active than the cyclohexane, dichloromethane, and ethyl acetate fractions. The relaxation induced by CECE and CEBF were inhibited by NG-nitro-L-arginine and affected neither by TRAM-34 plus UCL 1684 nor by indomethacin. CEBF induced sustained endothelium-dependent relaxations for at least 60 min, and inhibited, in a concentration-dependent manner, contractions to KCl, CaCl2, U46619 and serotonin in rings with endothelium. Analysis of CEBF by LCHRMS indicated the presence of polyphenols, terpenes, and alkaloids. Exposure of coronary artery and aorta rings to CEBF caused the accumulation of polyphenols predominantly in the endothelium. ConclusionC. edulis leaf extract induced pronounced endothelium-dependent relaxations and inhibited contractile responses by stimulating the endothelial formation of NO. LCHRMS analysis of the most active fraction, the butanolic fraction, revealed the presence of numerous compounds including polyphenols, terpenes, and alkaloids. The polyphenols of CEBF accumulated preferentially in the endothelium of the arterial wall. Thus, these observations support the folkloric use of C. edulis in hypertension.

Standardized Rat Coronary Ring Preparation and Real-Time Recording of Dynamic Tension Changes Along Vessel Diameter

As a key event of cardiovascular system diseases, coronary artery disease (CAD) has been widely regarded as the main culprit of atherosclerosis, myocardial infarction, and angina pectoris, which seriously threaten the life and health of people all over the world. However, how to record the dynamic biomechanical characteristics of isolated blood vessels has long puzzled people. Meanwhile, precise positioning and isolation of coronary arteries to measure in vitro dynamic vascular tension changes have become a trend in CAD drug development. The present protocol describes the macroscopic identification and microscopic separation of rat coronary arteries. The contraction and dilation function of the coronary artery ring along the vessel diameter was monitored using the established multi myograph system. The standardized and programmed protocols of coronary ring tension measurement, from sampling to data acquisition, tremendously improve the repeatability of the experimental data, which ensures the authenticity of vascular tension records after physiological, pathological, and drug intervention.

Activation of APJ Receptors by CMF‐019, but not Apelin, Causes Endothelium‐Dependent Relaxation of Spontaneously Hypertensive Rat Coronary Arteries

Hypertension is a major risk factor for coronary artery disease, but the pathophysiological mechanisms linking these diseases are not completely understood. Apelin is a novel vasoactive adipokine. Receptors for apelin (APJ receptors) are G‐protein‐coupled receptors and are widely expressed throughout the cardiovascular system. APJ receptors can also signal via G‐protein‐independent pathways, including G‐protein‐coupled‐receptor kinase 2 (GRK2), which inhibits nitric oxide synthase (eNOS) activity and nitric oxide (NO) production in endothelial cells. Apelin causes endothelium‐dependent, NO‐mediated relaxation of coronary arteries from normotensive animals, but the effects of activating APJ receptor signaling pathways in hypertensive coronary arteries are unknown. Since endothelium‐dependent relaxations are often blunted in arteries from hypertensive animals, we tested the hypothesis that apelin‐induced relaxation is impaired in coronary arteries from spontaneously hypertensive rats (SHR). Moreover, we hypothesized that endothelium‐dependent relaxations in response to CMF‐019, an APJ receptor G‐protein biased agonist with little effect on GRK2, would be unaffected in SHR coronary arteries. Western blot and RT‐qPCR analysis demonstrated that APJ receptor protein and mRNA expression did not differ between normotensive WKY (Wistar‐Kyoto) and SHR coronary arteries. eNOS protein expression was also similar between SHR and WKY coronary arteries, but GRK2 expression was significantly increased in SHR coronary endothelial cells, as compared to WKY. In myograph studies, apelin (10‐9‐10‐6 M) caused endothelium‐dependent relaxation of isolated WKY coronary arterial rings (pD2= 7.00 ± 0.11; Emax= 54 ± 4% relaxation; n=6), but had no effect in arteries from SHR. By contrast, CMF‐019 (10‐9‐10‐6 M)‐induced relaxation did not differ between normotensive and hypertensive coronary arteries. The relaxation response to CMF‐019 was abolished by the APJ receptor antagonist, F13A (10‐7 M), by removal of the endothelium, and by inhibition of eNOS with nitro‐ L‐arginine (3 x 10‐5 M). Moreover, the GRK2 inhibitor, CMPD 101 (3 x 10‐5 M), partially restored the relaxation response to apelin in SHR coronary arteries (pD2= 6.56 ± 0.22; Emax= 46 ± 6% relaxation; n=6). Immunoblot analysis of SHR coronary endothelial cells demonstrated that CMF‐019 (10‐7 M) significantly increased eNOS phosphorylation whereas apelin (10‐7 M) had no effect. We conclude that apelin failed to cause relaxation in hypertensive coronary arteries, likely due to impaired eNOS activity resulting from APJ receptor signaling via the GRK2 pathway and decreased eNOS phosphorylation. APJ receptor activation by the biased agonist, CMF‐019, caused similar endothelium‐dependent relaxations in WKY and SHR coronary arteries. Thus, APJ receptor‐biased agonists, such as CMF‐019, may be more effective than apelin in causing vasodilation of hypertensive coronary arteries.

Taxifolin as a Major Bioactive Compound in the Vasorelaxant Effect of Different Pigmented Rice Bran Extracts.

Cardiovascular disease is one of the leading causes of morbidity and mortality in recent years. The intake of polyphenol rich diets has been associated with improved cardiovascular function and reduced cardiovascular risks. Oryza sativa L. is one of the most common cereals worldwide. Rice bran, a byproduct of the rice milling process, contains many bioactive ingredients, including polyphenols, polysaccharides, proteins, and micronutrients. It is also consumed as a healthy diet in the form of rice bran oil and powder in many Asian countries like Japan, South Korea, and India for its several health benefits as a natural antioxidant. Thus, this study evaluated the vasorelaxant effect of ethanolic extracts of brown, green, red, and black rice bran and investigated its underlying vasorelaxant mechanism. Among the four rice bran extracts (RBEs) examined, the red rice bran extract (RRBE) had a strong endothelium-dependent vasorelaxant effect, which was markedly prevented by N-ω-nitro-L-arginine [endothelial nitric oxide synthase (eNOS) inhibitor], wortmannin [phosphoinositide-3 kinase (PI3K) inhibitor], and 1H-[1,2,4]oxadiazole[4,3-alpha]quinoxalin-1-one (inhibitor of guanylate cyclase). Likewise, RRBE induced the phosphorylation of eNOS and Src in cultured endothelial cells, thereby stimulating NO formation. Altogether, these findings propose that RRBE induces endothelium-dependent relaxation, involving at least in part, NO-mediated signaling through the PI3K/eNOS pathway. Further, LC-PDA analysis conducted on the four RBEs also revealed that RRBE highly contained taxifolin, which is an active flavanonol that induces endothelium-dependent vasorelaxation, compared to other RBEs. Subsequently, the underlying mechanism of taxifolin was assessed through vascular reactivity studies with pharmacological inhibitors similar to that of RRBE. These findings deciphered a distinct difference in vasorelaxant effects between RRBE and the other RBEs. We also observed that RRBE induced a potent endothelium-dependent NO-mediated relaxation in coronary artery rings, which involved the Src/PI3K pathway that activates eNOS. Additionally, taxifolin exhibited, at least in part, similar vasoprotective effects of RRBE. Therefore, we propose that RRBE may serve as natural sources of functional phytochemicals that improve cardiovascular diseases associated with disturbed NO production and endothelial dysfunction.

Beneficial Effects of Caffeic Acid Phenethyl Ester on Wound Healing in a Diabetic Mouse: Role of VEGF and NO

Cutaneous wound healing is delayed in patients with diabetes. Caffeic acid phenethyl ester (CAPE) has been identified as an effective constituent of propolis with improved wound healing abilities via an oxidative stress decrease. However, its impact on wound healing in diabetic models and its underlying mechanisms remain unclear. Determining the vascular endothelial growth factor (VEGF) contents in a human vascular smooth muscle cell (VSMC)-conditioned medium was assessed using human VEGF immunoassay and vascular reactivity using porcine coronary artery rings. Later, C57BL/6 or db/db mice were anesthetized, after which a 6-mm biopsy punch was manipulated for perforation via the back skin. Subsequently, CAPE was applied to the wound and changed daily. Furthermore, the injury in each mouse was digitally photographed, and the wound area was quantified. We observed that CAPE increased VEGF levels in human VSMC-conditioned medium, improved endothelium-dependent nitric oxide (NO)-mediated vasorelaxation, inhibited U46619-induced vasoconstriction porcine coronary artery, and enhanced cutaneous wound healing in the diabetic mouse model. Hence, we propose that CAPE improves wound healing in diabetic mice, which is aided by increased VEGF and NO expression.

Immunoneutralization of human angiotensin-(1-12) with a monoclonal antibody in a humanized model of hypertension

We engineered a monoclonal antibody (mAb) against the human C-terminus of angiotensin-(1–12) [h-Ang-(1–12)] and performed a biochemical characterization in concert with direct in vivo and ex vivo (carotid artery strips) assessments of h-Ang-(1–12) vasoconstrictor activity in 78 (36 females) transgenic rats expressing the human angiotensinogen gene [TGR(hAGT)L1623] and 26 (10 female) Sprague Dawley (SD) controls. The mAb shows high specificity in neutralizing angiotensin II formation from h-Ang-(1–12) and did not cross-react with human and rat angiotensins. Changes in arterial pressure and heart rate in Inactin® hydrate anesthetized rats were measured before and after h-Ang-(1–12) injections [dose range: 75–300 pmol/kg i.v.] prior to and 30–60 minutes after administration of the h-Ang-(1–12) mAb. Neutralization of circulating Ang-(1–12) inhibited the pressor action of h-Ang-(1–12), prevented Ang-(1–12) constrictor responses in carotid artery rings in both SD and TGR(hAGT)L1623 rats, and caused a fall in the arterial pressure of male and female transgenic rats. The Ang-(1–12) mAb did not affect the response of comparable dose-related pressor responses to Ang II, pre-immune IgG, or the rat sequence of Ang-(1–12). This h-Ang-(1–12) mAb can effectively suppress the pressor actions of the substrate in the circulation of hypertensive rats or in carotid artery strips from both SD and transgenic rats. The demonstration that this Ang-(1–12) mAb by itself, induced a fall in arterial pressure in transgenic hypertensive rats supports further exploring the potential abilities of Ang-(1–12) mAb in the treatment of hypertension.

Nanoencapsulation of the omega-3 EPA:DHA 6:1 formulation enhances and sustains NO-mediated endothelium-dependent relaxations in coronary artery rings and NO formation in endothelial cells

• Omega-3fatty acids stimulate the endothelial formation of vasoprotective nitric oxide. • EPA:DHA 6:1 nanoparticles caused greater sustained endothelium-dependent relaxation. • EPA:DHA 6:1 nanoparticles caused sustained formation of NO in endothelial cells. • EPA:DHA 6:1 nanoparticles-treated endothelial cells had greater anti-platelet effect. The eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) formulation with a ratio of 6:1 is a potent stimulator of the endothelial formation of nitric oxide (NO). The aim of the study was to investigate whether nanoencapsulation of EPA:DHA 6:1 followed by coating with gum increases its biological activity. Vascular reactivity was assessed using porcine coronary artery rings, the formation of NO in cultured endothelial cells (ECs) using DAF-FM and indirectly by platelet aggregation studies. Coated EPA:DHA 6:1 nanoparticles induced sustained relaxations of coronary artery rings that were greater in rings with than in those without endothelium, and more pronounced than with the native form. Treatment of ECs with coated EPA:DHA 6:1 nanoparticles caused greater and more sustained formation of NO and enhanced their anti-aggregatory effects. Thus, nanoencapsulation of EPA:DHA 6:1 is an attractive strategy to enhance the beneficial effect at the vascular endothelium.

Protective effects of dapagliflozin on vascular remodeling in the carotid artery following balloon injury – potential role of angiotensin and purinergic signaling

Abstract Introduction Sodium-glucose co-transporter 2 (SGLT2) inhibitors have been shown to reduce the risk of cardiovascular events independently of glycemic control. The possibility that SGLT2 inhibitors improve endothelial regeneration and vascular restenosis is unknown. Purpose To examine whether dapagliflozin, a selective SGLT2 inhibitor, could prevent neointima thickening induced by balloon injury and, if so, to determine the underlying mechanisms. The effect of dapagliflozin was compared to that of losartan, an angiotensin type 1 receptor (AT1R) antagonist. Methods Saline, dapagliflozin (1.5 mg/kg/day), or losartan (30 mg/kg/day) were administered orally for 5 weeks to male Wistar rats. Balloon injury of the left carotid artery was performed 1 week after starting the treatment and sacrificed 4 weeks later. Vascular reactivity was assessed on left (injured) and right (healthy) carotid artery rings. The extent of neointima was assessed by histomorphometric analysis, changes of target factors by immunofluorescence, RT-qPCR and histochemistry. Results Dapagliflozin and losartan treatments reduced neointima thickening by 32% and 27%, respectively. Blunted contractile responses to phenylephrine and relaxations to acetylcholine and down-regulation of eNOS were observed in the injured artery. These effects were not modified by the dapagliflozin or the losartan treatments. RT-qPCR investigations indicated an increased in gene expression of inflammatory (IL-1beta, ITGAM, VCAM-1), oxidative (p47phox, p22phox) and fibrotic (TGF-beta1) markers and a decreased of eNOS in the injured carotid. However, these changes were not affected by the pharmacological treatments. By contrast, significant increased levels of AT1R angiotensin receptor and NTPDase1 (CD39) ectonucleotidase were observed in the restenotic carotid artery of the dapagliflozin group. Histochemical analysis evidenced important NTPDase1 activity in the neointima. Conclusions Dapagliflozin effectively reduced neointimal thickening. As the contribution of AT1R and P2Y2 ATP receptor in smooth muscle cell proliferation and neointima formation has been reported in the literature, the present data suggest that dapagliflozin prevents restenosis through interfering with angiotensin and/or extracellular nucleotides signaling. SGLT2 transporter represent potential new target for limiting vascular restenosis. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): This work was supported by AstraZeneca

Case Report: Congenital Coronary Artery Ring With Single Left Coronary Ostium and Fistula: A Previously Unreported Anatomy

Background: Single coronary ostium concomitant with coronary artery fistula is a very rare congenital anomaly. Apart from that, the combination of a closed loop of the coronary artery has never been reported.Case presentation: Herein, we present a 7-year-old girl diagnosed as single left coronary ostium with a giant coronary trunk, coronary artery to right ventricle fistula, and coronary artery ring. The coronary fistula was surgically ligated with off-pump strategy and the patient discharged on postoperative day 5 and free of symptoms during the 3 years of follow-up.Conclusion: To our knowledge, the presented congenital coronary anomaly is the first to be reported in the literature with the name of congenital coronary artery ring with single left coronary ostium and fistula.

Methylglyoxal augments uridine diphosphate-induced contraction via activation of p38 mitogen-activated protein kinase in rat carotid artery

The methylglyoxal elicits diverse adverse effects on the body. Uridine diphosphate, an extracellular nucleotide, plays an important role as a signaling molecule controlling vascular tone. This study aimed to evaluate the relationship between methylglyoxal and uridine diphosphate-induced carotid arterial contraction in rats. Additionally, we examined whether p38 mitogen-activated protein kinase (MAPK) would involve such responses. Organ baths were conducted to determine vascular reactivity in isolated carotid arterial rings, and western blotting was used for protein analysis. Treatment with methylglyoxal to carotid arterial rings showed concentration-dependent augmentation to uridine diphosphate-induced contraction in the absence and presence of NG-nitro-L-arginine, which is a nitric oxide synthase inhibitor, whereas, methylglyoxal did not affect serotonin- or isotonic high K+-induced contraction in the presence of a nitric oxide synthase inhibitor. Under nitric oxide synthase inhibition, SB203580, which is a selective p38 MAPK inhibitor, suppressed uridine diphosphate-induced contraction in both the control and methylglyoxal-treated groups, and the difference in uridine diphosphate-induced contraction was abolished by SB203580 treatment. The levels of phosphorylated p38 MAPK were increased by methylglyoxal in carotid arteries, not only under the basal condition but also under uridine diphosphate stimulation. The suppression of uridine diphosphate-induced contraction by a highly selective cell-permeable protein kinase C inhibitor bisindolylmaleimide I was observed in the methylglyoxal-treated group but not in the controls. Moreover, methylglyoxal-induced augmentation of uridine diphosphate-induced contraction was prevented by N-acetyl-L-cysteine. These results suggest that methylglyoxal could enhance uridine diphosphate-induced contraction in rat carotid arteries and may be caused by activation of p38 MAPK and protein kinase C and increased oxidative stress.